Record early ice melt in Greenland due to freak warm weather

After record low amounts of sea ice across the Arctic Ocean last winter, spring has begun with an unprecedented early melt of land ice on Greenland.

Temperatures soaring above 10 °C caused more than a tenth of the island’s vast ice sheet to start melting on Monday and Tuesday this week, says Ruth Mottram of the Danish Meteorological Institute in Copenhagen.

Previously, the earliest melting recorded over more than a tenth of Greenland was on 5 May 2010, Mottram said. Normally, significant melting does not begin there until at least mid-May.

By Fred Pearce

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The melt was driven primarily by weather fronts bringing warm air and heavy rain from the Atlantic Ocean to the south of the island, she says.

Meteorological records dating back to 1873 show temperatures this week are a record high for the time of year. “This would be a warm day in July, never mind April,” said Robert Fausto of the Geological Survey of Denmark and Greenland, in a blog post on Tuesday.

Percolating heat

The Greenland ice sheet is up to 3 kilometres high and holds sufficient ice to raise sea levels by 6 metres if it all melted. Summer melting has been increasing since accurate records began in the 1970s.

Mottram says cold weather could return to southern Greenland any day, and the melted water and rain may refreeze.

“But there is some evidence that water that refreezes can precondition the snowpack to more rapid melt later on in the summer.” This is because, as it percolates into the snow, it takes heat with it.

The Arctic has been warmer than usual all winter. The maximum sea ice cover of 14.5 million square kilometres, measured on 24 March, was the smallest ever recorded, according to the US National Snow and Ice Data Center. “But we can’t really link the early melt [on Greenland] to the low sea ice,” says Mottram.

Some climatologists believe there may be a link nonetheless. Jennifer Francis of Rutgers University in New Jersey argued in February that the loss of Arctic ice was slowing the jet stream, an upper atmosphere air flow, and driving changes in weather patterns that channel more warm moist air over Greenland – exactly what happened this week.